A conventional plasma processing apparatus, for example a plasma processing apparatus 1 as shown in FIG. 3, has an apparatus main body 2 and auxiliary equipment 3. The apparatus main body 2 has a processing chamber 4 in which a sequence of processes is carried out on objects to be processed such as semiconductor wafers or glass substrates, for example oxide film formation processing of forming an oxide film, etching processing, and ashing processing. The auxiliary equipment 3 has a VHF apparatus (hereinafter referred to as the “power supply apparatus”) 5 that supplies power to the processing chamber 4 in which the sequence of processing is carried out on the semiconductor wafers, and a plurality of dry pumps 6 and 7 that are connected to the apparatus main body 2.
The power supply apparatus 5 is comprised of a matching unit 9 that is connected to the processing chamber 4 via a power-feeding rod-shaped cable 8, a circulator 11 that is connected to the matching unit 9 via a coaxial cable 10, and a power controller 12.
The power controller 12 has therein an RF amplifier 13 and a DC amplifier 14 that are formed in one body; a commercial power source 16 is connected to the DC amplifier 14 via a cable 15, and the RF amplifier 13 is connected to the circulator 11 via a coaxial cable 17. The coaxial cable 17 has high flexural rigidity, and is high in price per unit length, and furthermore the power loss is high when power is transmitted at high frequency (i.e. radio frequency (RF)) in particular, and hence it is desirable to make the wiring length as short as possible.
Usually, the apparatus main body 2, the matching unit 9 and the circulator 11 of such a plasma processing apparatus 1 are disposed in a clean room A upstairs, and the dry pumps 6, 7 and so on, and the power controller 12 of the power supply apparatus 5, which are permitted to be disposed in a space having a low degree of cleanliness, are disposed in a utility section B downstairs, whereby the footprint of the clean room, in which a high degree of cleanliness is required, can be reduced.
However, if the circulator 11 is disposed upstairs and the RF amplifier 13 is disposed downstairs as described above, then the wiring length of the coaxial cable 17 that connects the circulator 11 and the RF amplifier 13 together becomes long, and hence there are problems such as the cost of the power supply apparatus 5 increasing, and the power loss when power is transmitted at high frequency increasing, and moreover the reproducibility and stability of the transmitted power dropping.
It is an object of the present invention to provide a plasma processing apparatus which permits reduction of the cost, as well as reduction of the loss of transmitted power.